In recent years, a wireless power supply system capable of wirelessly supplying electric power from the power-supplying side to the power-receiving side of the system has been actively developed. Such a wireless power supply system can supply electric power without connecting the power-supplying side and the power-receiving side through wiring (cables), and has high convenience. Therefore, the wireless power supply system is regarded as a promising system used for charging a battery mounted on a vehicle such as an electric vehicle (EV) or a hybrid vehicle (HV).
The wireless power supply system used for charging a battery mounted on a vehicle includes a power-transmitting coil which, for example, is installed on the ground surface of a parking space (a parking area) provided within a parking lot or is buried in the parking space to be flush with the ground surface. The wireless power supply system wirelessly supplies electric power from the power-transmitting coil to a power-receiving coil provided in a vehicle parked in the parking space. If the vehicle is parked so that the power-receiving coil provided in the vehicle has an appropriate positional relationship (for example, a positional relationship in which the power-receiving coil overlaps with the power-transmitting coil in plan view) with respect to the power-transmitting coil, wireless power supply is efficiently performed.
Patent Document 1 discloses a wireless power supply system in which during supply of electric power, projection-shaped shield members surround the perimeter of an area positioned between a primary self-resonance coil transmitting electric power and a secondary self-resonance coil receiving electric power transmitted from the primary self-resonance coil. In this wireless power supply system, the resonance frequency of the shield members is set to a value between the resonance frequency of the primary and secondary self-resonance coils and the frequency of triple the resonance frequency of the primary and secondary self-resonance coils, thereby reducing electromagnetic waves leaking to the outside of the shield members.
Patent Document 2 discloses a wireless power supply system which includes a power-transmitting-side shield provided in a power-transmitting-side coil, and a power-receiving-side shield provided in a power-receiving-side coil.
Patent Document 3 discloses a bag-shaped shield member which is provided between a power-transmitting coil and a power-receiving coil of a wireless power supply system and which is capable of swelling and shrinking. Patent Document 4 discloses a shield member surrounding a coil unit of a wireless power supply system. Patent Document 5 discloses a shield member in which metal material having high magnetic permeability is applied to the surface of the shield member. Patent Document 6 discloses a power-transmitting coil including a cover member used for removing a foreign object.
Patent Document 7 discloses a flap-type wheel chock provided in a vehicle-parking lot. Patent Document 8 discloses a pedal movable due to the weight of a wheel and a power-transmitting coil which moves up and down simultaneously with movement of the pedal.